1. Technical Field
The invention relates to coaxial connectors that switch a signal path, such as a connector embedded in a mobile communication device.
2. Description of the Related Art
Japanese Unexamined Patent Application Publication No. 2002-42991 (“the '991 application”) describes a traditional coaxial connector. That coaxial connector is described below with reference to FIGS. 10 and 11 of the drawings. FIG. 10 shows a cross-sectional structure of a coaxial connector 110 described in the '991 application. FIG. 11 is an external perspective view that shows a casing 118, a movable terminal 120, and a fixed terminal 122 of the coaxial connector 110. In FIGS. 10 and 11, the z-direction is a direction in which an external terminal 114, a casing 116, and the casing 118 are placed. The x-direction is a direction in which the movable terminal 120 and the fixed terminal 122 are arranged. The y-direction is a direction perpendicular to the x-direction and the z-direction.
As shown in FIG. 10A, the coaxial connector 110 includes a main body 112, the movable terminal 120, and the fixed terminal 122. The main body 112 is made up of the external terminal 114 and the casings 116 and 118.
As shown in FIG. 11, the movable terminal 120 and the fixed terminal 122 are attached on the casing 118. The fixed terminal 122 is attached in the positive x-direction and includes a fixing portion 148 and a contact portion 150. As shown in FIG. 10A, the fixing portion 148 is disposed between the casing 116 and the casing 118 and fixes the fixed terminal 122 to the main body 112. The contact portion 150 protrudes from the fixing portion 148 in the negative x-direction.
The movable terminal 120 is attached in the negative x-direction and includes a fixing portion 142, a plate spring portion 144, and a contact portion 146. As shown in FIG. 10A, the fixing portion 142 is positioned between the casing 116 and the casing 118 and fixes the movable terminal 120 to the main body 112. The plate spring portion 144 extends in the y-direction and is in contact with the casing 118 at its both ends. In addition, the plate spring portion 144 has a shape that is curved so as to protrude in the positive z-direction. The contact portion 146 protrudes from the central part of the plate spring portion 144 in the y-direction to the positive x-direction and is pressed in contact with the contact portion 150 by an urging force of the plate spring portion 144.
The coaxial connector 110 having the above-described structure is provided, for example, between an antenna and a transmitter-receiver circuit of a cellular phone. Specifically, the fixed terminal 122 is connected to the antenna, and the movable terminal 120 is connected to the transmitter-receiver circuit. Typically, the movable terminal 120 and the fixed terminal 122 are in contact with each other, so the antenna and the transmitter-receiver circuit are connected to each other. Meanwhile, to measure electric characteristics of a transmitter-receiver circuit of a cellular phone by a cellar phone manufacturer, as shown in FIG. 10B, a probe 130 connected to a measuring device is inserted into the main body 112 from the positive to negative z-direction. Then, the probe 130 presses the plate spring portion 144 down, and this separates the contact portion 146 and the contact portion 150 from each other. As a result, the probe 130 and the movable terminal 120 become connected to each other, and the transmitter-receiver circuit and the measuring device become connected to each other.
Incidentally, for the coaxial connector 110, as shown in FIG. 11, the plate spring portion 144 extends in the y-direction. In order to exhibit an appropriate elastic force, the plate spring portion 144 needs to have a sufficient length in the y-direction. Because of this, in a signal path formed by the movable terminal 120 and the fixed terminal 122, the plate spring portion 144 is wider than other sections (e.g., the fixing portions 142 and 148). As such, when the plate spring portion 144 is wider than other sections, impedance matching in the plate spring portion 144 is undone. As a result, a radio-frequency characteristic of the coaxial connector 110 deteriorates.